DESCRIPTION (provided by candidate): [unreadable] This project will apply recent advances in cine 3D phase-contrast (PC) magnetic resonance imaging (MRI) to evaluate the interatrial blood flow in a clinical series of 60 consecutive stroke patients admitted to our institution, with the goal of characterizing patent foramen ovale (PFO) lesions and comparing these results with the results of "gold standard" transesophageal echocardiography (TEE). Phase-contrast MRI is a well established method for visualizing and quantifying physiologic motion and has been widely applied to a number of applications and has recently been extended to enable time-resolved 3D PC MRI (4D-Flow MRI). Unfortunately, in order to evaluate cardiac blood flow using 4D-Flow, a scan time of roughly 15 minutes is needed. MR imaging can be made faster by using arrays of multiple RF receiver coils to sample the MR signal simultaneously in a partially parallel acquisition method. This method uses prior knowledge of the coil sensitivity profiles to reduce the number of k-space samples needed for reconstruction. These parallel imaging methods will be applied to 4D-Flow MRI, enabling the addition of the sequence to the MRI examination received by 60 of the patients recruited for the original project evaluating the use of parallel imaging techniques in brain imaging of stroke patients. This data will then be used to characterize PFO lesions, which can serve as sources of "paradoxical emboli" causing ischemic stroke. Identification of these lesions is clinically relevant due to the risk of recurrent stroke and the increasing ability to effect definitive repair with low risk percutaneous catheter-based methods. MRI results will be compared with the results of TEE. Parallel 4D-Flow will also be used to generate cardiac- and respiratory-phase resolved cine images of the hearts of 10 normal volunteers and 10 stroke patients with known PFO. This will be combined with high resolution [unreadable] 3D cine anatomic imaging to begin exploring the potential replacement of TEE with MRI in [unreadable] evaluating cardiac etiologies of stroke. As MRI is less invasive that TEE, this could yield significant [unreadable] improvement in patient care. [unreadable] [unreadable]